Here is an example of how to use the HTMLLayoutBase class from the logback library in Java:

import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.FileAppender;
import ch.qos.logback.core.encoder.Encoder;
import ch.qos.logback.core.html.HTMLLayout;

public class Example {
    public static void main(String[] args) {
        Logger logger = (Logger) LoggerFactory.getLogger("ExampleLogger");

        FileAppender<ILoggingEvent> appender = new FileAppender<ILoggingEvent>();
        appender.setFile("example.html");

        HTMLLayout layout = new HTMLLayout();
        layout.setTitle("Example Log");
        layout.setPattern("%level %msg%n");
        layout.start();

        Encoder<ILoggingEvent> encoder = new LayoutWrappingEncoder<ILoggingEvent>();
        ((LayoutWrappingEncoder) encoder).setLayout(layout);
        appender.setEncoder(encoder);

        appender.start();
        logger.addAppender(appender);

        logger.debug("This is a debug message.");
        logger.info("This is an info message.");
        logger.warn("This is a warn message.");
        logger.error("This is an error message.");
    }
}

This example shows how to use the HTMLLayoutBase class to format log messages in HTML format. It creates a HTMLLayout object, sets the title of the page to "Example Log" and the pattern of the log to %level %msg%n and starts the layout. Then it creates a FileAppender object that writes the logs to a file called